Waste material inflow into resource limited landfills is strained by the voluminous amount of post consumer carpet waste produced by carpet distributors and carpet installation contractors and post industrial carpet waste produced by carpet manufacturers. Post industrial carpet waste can include, for example, commercial, industrial and residential carpet waste; manufacturing remnants; quality control failures, and the like. Post consumer carpet waste can be, for example, used carpet, e.g., carpet removed from a home, apartment complex, or a commercial installation, or unused carpet, e.g., residual carpet left from an installation or manufacturing process. While most estimates indicate that carpet waste constitutes only 1 to 2% of all municipal solid waste, this amount still represents a vast quantity of waste that can have a substantial economic and environmental impact.
The carpet waste inflow into landfills is not generally environmentally beneficial. In an effort to mitigate the amount of carpet waste that is shipped to landfills, efforts are being made to manually recycle at least a portion of the carpet waste prior to insertion into the landfill waste stream. Recycling carpet, however, is difficult because its major components are chemically and physically diverse.
Most carpets comprise about 20-50 percent weight face fiber, the remainder being backing materials, commonly polypropylene, and an adhesive which attaches the carpet fiber to the backing material. The adhesive typically comprises a carboxylated styrene-butadiene (XSB) latex copolymer, and inorganic filler like calcium carbonate. These materials are frequently incompatible with each other in a recycling operation. For example, the means used to separate and reuse a layer of the backing material might affect the usefulness of the pile material. Alternatively, a chemical used in the recycling process might dissolve two or more of the components, causing them to intermix and form a blend of the two materials having less desirable properties. The application of heat to melt certain materials can have the same effect. Because of these difficulties, to date the amount of carpet reclaimed through recycling operations is limited and only a minimal percentage of the total carpet waste may be useful in the production of green technology products. Accordingly, there is a need for efficient recycling of post industrial and post consumer carpet waste to reduce the amount of waste being disposed of at landfills.
In light of the various shortcomings of prior attempts to effectively recycle spent carpeting, a need is recognized for a system and method capable of effectively and efficiently separating the constituent materials of used carpeting, so that those materials can be effectively recycled into new product with a minimum of discarded material and a minimum need to add virgin material to reduce contamination levels.
A further need is recognized for a scheme that makes effective and efficient use of the reclaimed materials in new carpeting. The need for virgin material should be kept to a minimum, in order to decrease costs and increase the amount of old material that is converted into new carpeting. In addition, such broad-based recycling methods can also potentially help to comport with National Sanitation Foundation (NSF) 140/2007 recommendations, which encourage carpet industries to develop sustainable carpet manufacturing and recycling programs for social, economic, and environmental benefits.